merged mods and engine for the Windows installer

closes #4052
recursivly copy the mods folder for NSIS
Merge pull request #4089 from Mailaender/nsis-consolidation

Consolidated Windows installer options
Fix a NRE in the exception handler.
Fix viceroid muzzle offsets and missing traits.
Fix orca missile trails.
Add contrails to C&C rocket weapons.
Load the main mod dlls for all mods. Fixes #4029.
Remove "Humans vs Bots" auto-team if bots are disabled. Fixes #4074.
SyncInfo is only valid during the initial lobby phase. Fixes #3973.

Existing broken replays can be fixed manually by removing the SyncInfo order at the end of the file.
Use selection priority in double-click selection logic. Fixes #4053.
Support custom helicopter rotors. Fixes #4072.
Update changelog. Fixes #4085.
Use non-bold checkbox labels in C&C.
Merge pull request #4100 from pchote/checkbox-font

Use non-bold checkbox labels in C&C.
bold → regular for lobby dropdowns
Merge pull request #4099 from ScottNZ/balance

Enable build speedup for ra
Merge pull request #4091 from pchote/crashception-fix

Fix a NRE in the exception handler.
Merge pull request #4092 from pchote/vice-fix

Fix viceroids and add contrails to C&C rockets.
Merge pull request #4093 from pchote/all-the-dlls

Load the main mod dlls for all mods. Fixes #4029.